The inventive concept relates to magnetic recording media. More particularly, the inventive concept relates to a perpendicular magnetic recording medium in which the direction of magnetization of bits of recorded data is perpendicular to the surface of a magnetic layer.
The amount of information or data that must be processed by today's electronic devices is constantly rapidly increasing. Accordingly, the data must be recorded (stored) with a high-density and the data must be capable of being recorded/reproduced at a rapid rate. In this regard, magnetic recording devices have characteristics such as large storage capacity and fast access time. Accordingly, magnetic recording devices are being widely used as information memory devices by various digital devices, as well as by computers. These magnetic recording devices employ a magnetic recording medium to record (store) data, and a magnetic head (having a magnetic recording mechanism and a reproducing sensor) to write data onto/read data from the magnetic recording medium.
A magnetic recording medium of a magnetic recording device may be of a longitudinal magnetic recording type or a perpendicular magnetic recording type according to the way in which the medium records (stores) data. In a longitudinal type of magnetic recording medium, the direction of magnetization of bits of recorded data is parallel to a surface of a magnetic layer. In a perpendicular type of magnetic recording medium, the direction of magnetization of bits of recorded data is perpendicular to the surface of the magnetic layer. Data can be recorded with a higher recording density on a perpendicular type of magnetic recording medium than on a longitudinal type of magnetic recording medium.
A conventional perpendicular magnetic recording medium includes a soft magnetic underlayer, a recording layer having tracks along which data is recorded, and a passivation layer. The intermediate layer is provided, in part, to impart a specific crystallographic orientation to the recording layer formed thereon. However, the intermediate layer must be at least about 20 nm if it is to have a sufficient affect on the crystallization of the recording layer. Furthermore, the intermediate layer is formed of a relatively expensive material such as Ru. Thus, the thick intermediate layer of the conventional perpendicular magnetic recording medium contributes a significant amount to the relatively high cost of manufacturing the medium.
The soft magnetic layer serves to attract the magnetic field generated by magnetic head during a recording (write) operation However, the magnetic head is spaced relatively far from the soft magnetic underlayer because the intermediate layer is interposed between the recording layer and the soft magnetic underlayer. Thus, magnetic field generated by the head to write data onto the recording layer is dispersed by the provision of the intermediate layer. That is, the intermediate layer counteracts the effect of the soft magnetic underlayer.